Brush holder assembly



nited States BRUSH HOLDER ASSEMBLY Filed Dec. 12, 1958, Ser. No. '780,099` 6 Claims. (Cl. 310-241) This invention relates generally to brush holder assemblies or brush rigging.n for dynamoelectric machines and more specifically to brush riggings that include brush holders of the reaction type that are pted to be mounted in more than one position relative to the commutator.

Recognized standard directions of rotation in nonreversing DJC. machines are clockwise for generators and counterclockwise for motors. Consequently, brush riggings which use reaction type brush holders will differ in brush holder orientation to suit the direction of rotation.

A reaction type brush holder is one which holds the longitudinal axis of the brush at an angle with respect to a radial line of the commutator. This angle, lmeasured yat the surface of the commutator where the brush axis intercepts a radial line, corresponds to the direction of the net force acting on the brush due to friction against the commutator surface and against the brush holder guides.

Prior art dynamoelect-ric machines teach two different brush rigging constructions to provide for clockwise and counterclockwise rotation of the machine. The more common of these two `constructions consists of mounting the individual brush holders on studs which are secured to the rocker ring in such a manner as to be equally spaced around the ring and have their axes parallel to the rotational axis of the machine. The second method involves mounting the brush holders directly on the rocker ring.

The brush rigging of this invention overcomes the problems of prior art brush riggings by calling for a single set of brush holders and one rocker ringv to which the holder may be tted for either clockwise or counterclockwise rotation of the motor armature. The holder of this invention utilizes a constant tension spring removably mounted on a brush holder that has a base mounted in a suitable slot on the rocker ring. The sides of the base are so formed that by merely inverting the base you can change the operating position of the brush Afrom counterclockwise to clockwise.

Therefore it is the object of this invention to provide a new and improved brush holder assembly for dynamoelectric machines.

Another object of this invention is to provide a new and improved brush holder assembly for dynamoelectric machines that can be positioned for either clockwise or couuterclockwise rotation of the motor armature.

Another object of this invention is to provide a new and improved brush holder assembly that is rugged in construction and which. is easily assembled and accurately positioned in a dynamoelectric machine.

`Other objects and advantages of this invention will be apparent from the following description when read in conjunction with the attached drawings 'L1 which:

Fig. 1 is a View partially in section showing the brush holder assembly of this invention mounted on a rocker ring of a dynamoelectric machine for counterclockwise rotation of the machine;

arent Aice Fig. 2 is a rear view of the holder shown in Fig. 1;

Fig. 3 is a side view of the holder shown in Fig. 1;

Fig. 4 is an end view, with parts broken away, of the brush holder shown in Fig. 3; f

Fig. 5 is a partial View showing the holder mounted on the rocker ring for clockwise rotation of the machine; and

Fig. 6 is atop view of the brush holder.

Referring more particularly to the drawings, the reaction type brush holder assembly 10 of this invention consists of a holder 11 comprising a casing 12 having a iirst channel 13 for receiving a carbon brush 15, a second channel 17 for receiving a spring assembly 19 and a base 20 having a novel configuration which is adapted for mounting in a slot 22 in the rocker ring 23 of a dynamoelectric machine. The first channel 13 can be of any suitable configuration for receiving a carbon brush in longitudinal sliding relation. As shown in Fig 1, the brush holder assembly is formed so that the vfirst channel forms a predetermined angle relative to the radius of the comrnutato-r 24 when the brush holder 11 is mounted in the rocker ring. rthe holder can be adjusted longitudinally in the slot to accurately position the brush relative to the commutator.

The carbon brush 1S is of the type normally used in dynamoclectric machines. The brush 15 is connected by a suitable `conductor 25 to the casing l2 which in turn is in Contact with conductors embedded in the rocker ring 23. v

'Qn the casing 12 adjacent to the first channel 13 is a second channel 17 especially adapted for receiving the spring assembly 19. As shown in Fig. 6 these channels 13, 1'7 are formed in the casing by inwardly extending ribs 26 that divide the casing into two compartments. The spring assembly generally consists of `a suitable support member with resilient means attached thereto. Speciiically as shown in the drawings, the assembly consists of a U- shaped support member 27 that has on one side an outwardly extending clip 28 which is designed to engage a suitable slot 29 in the rear surface 30 of the casing 12 for retaining the support member with the connes of the second channel. The resilient means are attached to the support member and are positioned to engage the top or" the brush in the first channel to urge the brush toward the commutator surface of the dynamoelectric machine.

The resilient means preferably consists of a constant tension spring 33 such `as the NEGATOR type spring. The spring d3 is formed of a relatively thin strip of spring metal that is prestressed prior to assembly so that it normally forms a spiral coil in its longitudinal direction. The spring 33 has one end 34 attached to the support member in any suitable way, such as by rivets, and the other end 35 which tends to remain coiled engages the top of the brush 15 positioned within the rst channel 13 to urge the brush in a longitudinal direction through the channel with a substantially constant pressure. The uniform pressure assures a good substantially constant contact of the brush with the commutator to reduce chattering.

Mounted on the casing 12 yat the open ends of the second channel 17 are retaining members 38 which extend across the opening in a transverse direction to the support member. 4In assembly, the leading edge 39 of the support member 27 is inserted beneath the retaining means 38 and moved until the sides of the U-shaped member 27 are substantially parallel to the sides of the second channel 17. The member 27 is then forced into the channel 17 until the clip 28 engages the slot 29 in the casing 12. In this arrangement the retaining members are intermediate the legs of the U-shaped member so that when the U- shaped member is released from the casing the bottom of the U-shaped member will engage the retaining means to prevent the support member from being removed entirely from the brush holder assembly while permitting the Support member to pivot around the retaining means.

When the support member 27 is pivoted around the retaining member 38, the spring no longer contacts the brush and the brush can be easily removed from the first channel for inspection or replacement.

The rocker ring 23 is suitably attached to the dynamoelectric machine and may be of any construction well known in the art. As shown in the drawings, the rocker ring has formed therein slots for receiving the base of the brush holder. For convenience the slots 22 are illustrated as substantially radial slots.

The base 20 of the brush holder 11 has two sets of cooperating surfaces 42, 43 which are adapted to independently engage the sides of the slot 22 in the rocker ring 23 to position the brush and brush holder at a predetermined angle relative to the radius of the commutator 24. As shown in Fig. 5, when surfaces 42 engage the sides of the slot 22 the brush is lpositioned for clockwise rotation of the armature and in Fig. l when surfaces 43 engage the sides of the slot the brush is set for counterclockwise rotation of the armature.

The surfaces -42 and 43 of the base can be at any suitable angle so long. las they will fit the corresponding sides of the slot. Therefore, the slot co-uld be at an angle other than perpendicular to the axis of rotation of the shaft as shown so long as the surfaces of the base were formed to cooperate with corresponding sides of the slot to properly position the holder relative to the commutator.

To assemble the brush holder rfor clockwise rotation of the armature as shown in Fig'. l, the base 20 is appropriately positioned in the slot 22 of the rocker ring and secured therein by suitable means such as the bolt 45. The brush 15 is then placed in the first channel 13 and the conductor 25 from the brush is secured to the terminal 46 on the side of the casing 12. The support member 27 is then inserted beneath the retaining member 38 `and clipped into the slot 29 in the holder casing. In this position the coiled end of the spring engages the top of the brush and urges it toward the commutator 24. r["his accurately land quickly positions the brush Ifor clockwise rotation of the armature.

When it is desired to rotate the armature in a counterclockwise direction, such Ias shown in Fig. 5, the support member 27 is released and removed from the second channel. The brush 15 is then removed and disconnected. The mounting bolt 45 is withdrawn and the brush holder 11 is inverted. The brush 15 is then reinserted in the first channel I13: but from the opposite end vand the support member is positioned in the second channel 17 and also from the opposite end. The holder is then positioned in the slot 22 in the rocker ring. However, in this position the second set of Surfaces 43 engage the sides of the slot to angle the brush holder at substantially the same angle relative to the'slot in the rock-er ring but on the opposite side of the slot from the first position. In this arrangement the brush is positioned relative to the commutator for counterclockwise rotation of the commutator.

Although but one embodiment has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing 4from the spirit of the invention or from the sco-pe of the appended claims.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

l. A brush holder assembly for a dynamoelectric m-achine having a commutator comprising: a holder having a channel defined therein, a brush mounted in said channel in sliding relation relative thereto, means for urging said -brush toward said commutator, means adapted to be connected to said machine for mounting said holder, each of said mounting means having a slot for receiving a holder, said holder having a base extending therefrom,

g said base having two sets of cooperating surfaces adapted to independently co-act with the sides of said slot to locate said holder in two distinct positions for clockwise and counterclockwise rotation of said commutator.

2. A brush holder assembly for a dynamoelectric machine having a commutator comprising: a holder having a channel defined therein, a brush mounted in said channel in sliding relation relative thereto, means for urging said brush toward said commutator, means adapted to be connected to said machine for mounting said holder, each of said mounting means having a substantially radial Slot for receiving a holder, said holder having a base extending therefrom, said base having two sets of cooperating surfaces adapted to independently coact with the sides of said slot to locate said holder in two distinct positions for clockwise and counterclockwise rotation of said commutator.

3. A brush holder assembly ffor a dynamoelectric machine having a commutator comprising: a holder having a channel, a brush mounted in said channel in sliding relation relative thereto, means for urging said brush toward said commutator, means adapted to be connected to said machine for mounting said holder, each of said mounting means having a substantially radial slot for 4. A brush holder assembly for a dynamoelectric ma-v chine having a commutator and a rocker ring; said assembly comprising Ia casing having a first and second channel, a brush mounted in said first channel in sliding relation relative thereto, means positioned in said second channel yfor urging said brush toward said commutator,

said means comprising a U-shaped member and a constant tension spring having one end attached to said member and its other end adapted to engage said brush, a retaining member extending across said second channel and positionable between the legs of said U-shaped member for engaging said U-shaped member when in its nonopenating position, a rocker ring adapted to be mounted on said machine and having surfaces defining a plurality of radial slots, a base extending from said casing and having two sets of surfaces that coact with a corresponding said radial slot in said rocker ring to locate said casing in two distinct positions for clockwise and counterclockwise rotation of said commutator.

5. `A brush holder assembly for 4a dynamoelectric machine having a commutator and a rocker ring; said assembly comprising a casing having a first and second channel, a brush mounted in said rst channel in sliding relation relative thereto, means positioned in said second channel for urging said brush toward said commutator, said means comprising a U-shaped member and a constant tension spring having one end [attached to said member and its other end adapted to engage said brush, said member having a clip for' engaging said casing to hold said member in said second channel, a retaining member extending across said second channel and posifiona-ble between the legs of said U-shaped member for engaging said U-shaped member when in its nonoperating position, a rocker ring adapted to be mounted on said machine and having surfaces defini-ng a plurality of radial slots, a base extending from said casing and having two sets of parallel surfaces that coact with a corresponding said radial slot in said rocker ring to locate said casing in two distinct positions for clockwise and counterclock- Wise rotation of said commutator.

6.- A brush holder assembly for a dynamoelectric machine having a commutator and a rocker ring; said assembly comprising a casing having a first and second l channel, a brush mounted in said first channel in sliding relation relative thereto, means positioned in said second channel for urging said brush toward said commutator, said means comprising a U-shaped member and a constant tension spring having one end attached to said member and its other end adapted to engage said brush, said member having `a. clip for engaging said casing to hold said member in said second channel, a retaining member extending `across said second channel at each end `and positionable between the legs of said U-shaped member for engaging said U-shaped member when in its nonoperating position, -a rocker ring adapted to be mounted on said machine and having surfaces deiining a plurality of radial slots, a base extending from said casing and having two sets of parallel surfaces that coact with a corresponding said radial slot in said rocker ring to locate said casing in two distinct positions for clockwise and counterclockwise rotation of said commu-tator.

References Cited in the le of this patent UNITED STATES PATENTS 

